Dynamic Performance Analysis of Hysteresis Motors by a Linear Time-Varying Model

Hysteresis motors are self starting brushless synchronous motors which arebeing used widely due to their interesting features. accurate modeling of the motors iscrucial to successful investigating the dynamic performance of them. the hysteresis loopsof the material used in the rotor and their influences on the parameters of the equivalentcircuit are necessary to be taken into consideration adequately. it is demonstrated that someof the equivalent circuit parameters vary significantly with input voltage variation and otheroperating conditions. in this paper, a comprehensive analysis of a hysteresis motor in thestart up and steady state regimes are carried out based on a developed d-q model of themotor with time-varying parameters being updated during the simulation time. theequivalent circuit of the motor is presented taking into account the major impact of theinput voltage. simulation results performed in matlab-simulink environment prove that theexisting simple models with constant parameters can not predict the motor performanceaccurately in particular for variable speed applications. swings of torque, huntingphenomenon, improvement of power factor by temporarily increasing the stator voltage andstart up behavior of the hysteresis machine are some important issues which can accuratelybe analyzed by the proposed modeling approach.